Utilizing beet-molasses waste water.



F. W. HUBER & R. W. POINDEXTER, JR.

UTILIZING BEET MOLASSES WASTE WATER.

APPLICATION FILED JULY 21.1914.

LM5A84I. Patented July 6, 1915.

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UNITED STAES rarnnrr o.

FREDERICK w. HUBER AND ROBERT w. rornnnx'rnn, an, or nos ANGELES,

CALIFORNIA.

UTILIZING BEET-MOLASSES WASTE WATER.

Specification of Letters Patent.

Patented July 6, 19115..

Application filed July 21, 191 3.. Serial No. 852,325.

To all whom it may concern:

Be it lrnown that we, FREDERICK W..HUBER and ROBERT "W. POINDEXTER, Jr.,both citizens of the United States, and both residing at Los Angeles, inthe county of Los Angeles and State of California, have invented certainnew and useful improvements in utilizing beet-molasses Waste waterresulting from the desugarization of beet-molasses by the Steffen ortricalcium-saccharate recess, of which the following is a specification.

()ur invention relates to the utilization of that residue or wastewater, usually known and hereinafter referred to as Steflens water,which results from the desugarization of beet molasses by thewell knownStefi'en process. The Stefi'en process efiects the extraction of thesugar from the molasses in the following manner: The molasses is dilutedtill it has a sugar content of 7% and to this diluted molasses is addedan amount of finely powdered quicklime equal to, or slightly in excessof, the total amount of sugar in the diluted molasses. The lime is addeda little at a time, and mixed by mechanical agitation, with artificialcooling. In this way the sugar is made to combine with the lime in theform of an insoluble precipitate of triealcium saccharate, from whichthe remaining solution, called Stettens water, is filtered 0E. Thetricalcium 'saccharate is subsequently treated so as to recover thesugar in pure form. The Stetiens water contains practically everythingexcept the sugar which was present in the original molasses. Especiallyimportant are the organic nitrogen compounds and potash salts which itcontains. Hitherto this Stefiens water has been either thrown away, orimperfectly utilized as a fertilizer, with or without concentration andadmixture with other substances.

The object of our invention is to utilize Stctlens water much morecompletely and advantageously, by obtaining from it certain valuableproducts, namely: potassium salts. ammonia or ammonium sulfate andhydrocyanic acid.

The accompanying drawing shows an apparatus which is suitable for use incarrying out our improved process, but the procrss can he carried out,if desired, in apparatus very diti'ercnt from that illustrated.

In said drawin ,Figure 1 shows a vertical section of a suita 1eapparatus, and Fig. 2,

shows a plan view of the same, portions belng shown in section.

Steti'ens water is concentrated by evaporation until it has a specificgravity of from 1.3 to 1.4.. It is then run, preferably Warm, throughpipes, a, a, a, on the accom anying drawing, into a system of retorts,A, A, in which it is heated in the absence of air, that is,destructively distilled. The retorts are heated by gas or any otherfuel. These retorts may be of iron, fire clay or any other suitablematerial. The temperature of the retorts must be high enough for theorganic compounds contained in the concentrated Steflens water to bedestructively distilled, so that gases and vapors containing ammount andallied compounds are driven ofi' with approximate completeness, andthere remains in the retort a black mass, consisting essentially of ashmixed with carbon.- A temperature of 500 0., has been found to give goodresults.

The retort gases are passed directly into one of two superheaters B, B,wherein the gases are highly superheated, which step converts a part ofthe nitrogen compounds, contained therein, into the form of hydrocyanicacid. These superheaters may be shells of iron or steel, lined withrefractory material, and filled with blocks or pieces of a materialwhich will resistthe temperature of about 1,000 C., which it isnecessary. to use. It is generally necessary to have two superheaters,so that while one is being used to superheat the gases from the retorts,the other can be heatedup preparatory to such use. Valves or dampers are.provided at d and (13' so that the retort gases may be made to passthrough either B or B. Thus the super-heating is made continuous. Theheating of the superheaters is accomplished by direct internal firing,using either gaseous or liquid fuel introduced for example at b and ablast of air introduced for example at 6 During the firing, the topvalve 6 is left open. When the gases and vapors from the retorts arepassed through the superheater, the heat which has been stored up in thefilling material is communicated to them by contact and radiation, andthey are thereby heated to the high temperature necessary for theformation of hydroeyanic acid.

We have found that passing the gases through the superheater as ra idlyas possible favors the formation 0 hydrocyanic passed through a coolerand tar acid, and also while it is Well known that ammonia tends todissociate into its elements at a temperature of 1060 (1, this reactionis quite slow and we find that by passing the gases rather rapidlythrough the heater, no appreciable amount of the ammonia is dissociated,during the time it is subjected to the action of the superheater.

The hot gases from the superheater are separator, (3, which removes fromthem tar and finely divided carbon. They are not cooled this point to atemperature low enough to condense the water vapor whica. they contain,so that it, and all substances of an equal or greater volatility, passon. The gases may be cooled to about 110 C. The

gases are now passed in at the bottom of the tower D, which isconstructed of, or lined with, an acid-prooi material, and filled withacid-proof filling material, in such a way as to leave spaces for thepassage of the gases. Sulfuric acid is sprayed in at the top of the towethrough the sprayer 7", in such a manner that it flows down and over thetower filling material and exposes a large surface to the ascendingcurrent of gases. By means of the sulfuric acid, the ammonia containedin the gases is absorbed, and converted into ammonium sulfate. This isdrawn off in solution through the pipe m, and obtained in solid form byevaporating the solution. The temperature of D is kept suiiiciently highto avoid the condensation of the water and hydrocyanic acid gascontained in the gas mixture, a temperature of about 110 (1, beingpreferred.

The gases coming from D are passed downward through the cooler E, whichmay be of iron or steel, and which contains a system of refrigeratingpipes adapted to cool the gases nearly to 0 C. In this cooler, most ofthe water and much of the hydrocyanic acid contained in the gas mixtureis condensed, and the resulting solution of hydrocyanic acid in waterflows out through the pipe 72. The gases pass on to the tower l5, whichhas for its object the removal of the remainder of the hydrocyanic acid.This tower may be similar in construction to the ammonia tower D, butdoes not need to be made or acid proof materials, as hydrocyanic acid istoo weak to attack ordinary metals. Through the sprayer g, the ascendinggases are washed with cold water, and the resulting dilute solution ofhydrocyanic acid passes out through the pipe at, where it mixes with thesolution from the cooler The dilute hydrocyanic acid may be concentratedin a column distilling apparatus or in other ways. The fact that weobtain hydrocyanic acid in liquid form by our process is of especialimportance. Hitherto, when it has been necessary to use hydrocyanic acidin the arts, and especially in fumigation of fruit trees, has beennecessary to prepare it at considerable expense by treating a cyanidorferrocyanid with an acid.

The gases passing out from F are combustible and may be used for heatingthe retorts, or the super-heaters, or for any other purpose.

The black mass which remains in the retorts, after the volatile matterhas been distilled oil, is removed and treated with water in vats madeof cement or other suitable material. this way a solution is obtainedwhich contains the potassium which was present in the original oteffenswater. Most of the potassium is in the form of the carbonate. This maybe obtained in solid form by evaporating the solution or the solutionmay be neutralized with any suit-able acid so as to give on evaporationthe corresponding salt. 7

By means of the process we have described, we have succeeded inconverting 55% of the nitrogen contained in Steffens water intohydrocyanic acid, 26% oi. it into ammonia, and recovering over of thepotassium present the Steiiens water the form of carbonate, or othersalts #Vhile the process has been described as particularly applied tothe treatment of Steilens water, we call attention to the that othersuitable liquids, which may or may not be mixed with solids may heemployed.

The treatment of the gases, by the method herein described, namely bypassing he same through a checker work heated to about 1000 (3.,followed by cooling to a gree suiiicient only to separate tarry matters,followed by treatment with acid to remove ammonia, followed by coolingand washing with water to remove hydrocyanic acid, al o is applicable tosimilar gases, however produced.

VJ hat we claim is l. The process of utilizing Steffens water 1;;

or the like which comprises concentrating said Steffen s water,subjecting the concentrated material to destructive distillation, inabsence of air, whereby gases containing ammonia allied nitrogenouscompounds resul", heating these gases to a temperature above a red heat,whereby a part of the nitrogen contained in them is converted intohydrocyanic acid, absorbing the ammonia by treating the gases with anacid, and therea "ter reco ering the hydrocyanicacid from the gases.

2. A process of separating ammonia and hydrocyanic acid from gasescontaining the same, which comprises subjecting said gases first to theaction of an acid stronger than hydrocyanic, to produce an ammoniumsalt, and thereafter treating said gases with water to absorb thehydrocyanic acid.

3. process of; separating tar, ammonia meaeee and hydrocyanic acid fromgases, which perature the eomlensecl waber will absorb ai; comprisesfirst cooling the gases to a temleast a part of the hydrocyamc acid,

perature at which the tarry matters con- In testimony whereof we afiixour signadense, but which temperature ig above that tures in presence oftwo Witnesses.

5 at which Water vapor carried y the gases would condense, thereafterWashing the JR gases with an acid, to produce an aonium sale, andthereafter cooling the gases who a Witnesses:

temperature at which the principaipart of NORMAN Iii Lineman, 10 theWater vapor will condense, at which tem- R. DAN. FRAME.

